1. Field of the Invention
The invention relates to a computer monitor, more particularly to a computer monitor having dual-purpose control switches, and to a method for providing screen-control switches on a computer monitor with different functions according to the presence (or absence) of a universal serial bus (USB) standard compliant-interface that is established with a computer.
2. Description of the Related Art
In one example of a conventional computer monitor, control knobs are provided to enable the user to adjust various characteristics, such as screen color and contrast, of the computer monitor. However, the adjustment as such relies only upon the eyes of the user and is unsuited for standardized adjustment.
Another example of a conventional computer monitor is capable of performing a hardware-based on-screen display (OSD) routine. With the use of screen-control switches on the computer monitor, the OSD routine can be initiated to enable the user to adjust the values of different screen characteristics that are shown on a screen of the computer monitor.
A further example of a conventional computer monitor is capable of establishing electrical connection with a personal computer via an interface that complies with the universal serial bus (USB) standard. By incorporating additional function keys on the computer monitor, control signals can be transmitted to the personal computer via the interface to expand the functionality of the computer monitor.
However, it is noted that the additional function keys on the computer monitor do not serve any purpose when the latter is used with a personal computer that does not support the USB standard. As such, manufacturers generally make two kinds of computer monitors, one supporting the USB standard, the other incapable of supporting the USB standard. This results in inconvenience during production and inventory management.
Therefore, the object of the present invention is to provide a computer monitor having screen-control switches that can be used to perform conventional screen characteristics adjustment under a normal operating mode, and to perform expanded control functions under a USB standard compliant-interface operating mode.
Another object of the present invention is to provide a method for providing screen-control switches on a computer monitor with different functions according to the presence (or absence) of a universal serial bus (USB) standard compliant-interface that is established with a computer.
According to one aspect of the invention, a computer monitor is adapted for use with a computer and comprises a plurality of screen-control switches, an input/output circuit adapted to be connected to the computer, and a processor connected to the screencontrol switches and the input/output circuit, and adapted to detect if a universal serial bus (USB) standard compliant-interface was established between the input/output circuit and the computer. The processor performs a hardware-based on-screen display routine to adjust screen characteristics of the computer monitor when the screen-control switches are operated and the USB standard compliant-interface is not detected. The processor generates a command that is assigned to an operated one of the screen-control switches and that is to be received by the computer via the USB standard compliant-interface when the USB standard compliant-interface is detected.
According to another aspect of the invention, a method for providing screen-control switches on a computer monitor with different functions, comprises:
detecting if a universal serial bus (USB) standard compliant-interface was established between the computer monitor and a computer;
when the USB standard compliant-interface is not detected, performing a hardware-based on-screen display routine internally of the computer monitor to adjust screen characteristics of the computer monitor when the screen-control switches are operated; and
when the USB standard compliant-interface is detected, generating a command that is assigned to an operated one of the screen-control switches and that is to be received by the computer via the USB standard compliant-interface.